Used when a cell needs to be compared with a key byte[] such as cases of finding the index from
the index block, bloom keys from the bloom blocks This byte[] is expected to be serialized in
the KeyValue serialization format If the KeyValue (Cell's) serialization format changes this
method cannot be used.

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C-tor to be used when new CellChunkImmutableSegment is built as a result of compaction/merge
of a list of older ImmutableSegments.